The Purposes of the Geisinger Clinical Oncology Program are to: 1) enter large numbers of patients with cancer into NCI-approved treatment and cancer control clinical trials, bringing state-of-the-art cancer care into a large rural population of Pennsylvania; 2) use the large, multispecialty group practice structure of the Geisinger Clinic to involve primary health care providers as well as a wider cross-section of medical and surgical specialists in cancer treatment and control research; and 3) extend cancer control efforts of the CCOP to the Geisinger System, involving a wide geographic area and many primary care practice sites with screening, detection, prevention, ongoing care, rehabilitation activities through CCOP protocols. There are many special aspects of Geisinger that favor continuation of our CCOP: 1.Large cancer patient population; huge overall patient numbers (over 1 million outpatient visits annually for the Geisinger System). 2.Stable, very experienced CCOP staff. 3.A 6-year record of successful accrual to both NCI-approved cancer treatment and cancer control protocols, with consistent, superb data quality. 4.Geisinger's excellent medical record system, with unit patient charts. 5.All needed treatment specialists available under one roof, with a large, full-time salaried multispecialty physician staff. 6.Geisinger CCOP's record of active involvement with research bases, with several protocol chairmanships, committee memberships, authored publications. 7.Our long-standing interest in cancer control research, as evidenced by prior in-house original studies, and cancer control protocols chaired for NCCTG. 8.Availability of large primary care network for future large scale control trials. 9.Very strong institutional commitment to clinical trials research in cancer. We propose that our CCOP retain the North Central Cancer Treatment Group as our primary base (includes a secondary affiliation with ECOG through Mayo Clinic). The Radiation Therapy Oncology Group and the Childrens' Cancer Study Group will be our secondary bases. This variety allows all the physicians to play a major role in their modality's group, not just as a "supporting character" for the medical oncologists. It also suits our tertiary care institution, since rare tumors are seen here with some frequency.